Pneumatic thread holder for looms



Nov. 25, 1947. L. .1.'HooPER ET AL 2,431,556

' PNEUMATIG THREAD HOLDER FoR'Loo'Ms Filed Dec. '13, 1946 2 Sheets-Sheet 1 INVENTORS LESLIE' J. HOOPE? VICTOR F. SEPAV/GH Nov. 25, 1947.y

PNEUMAT L. J. HOOPER ET AL IC THREAD HOLDER FOR LooMs Filed Dec'. 15, 194e 2 sheets-'sheet '2 INVENToRs ESL/E J. Hoops/i v/crof? FQ sEPAV/OH Kai VTM@ ATTORNEY Patented Nov. 25, 1947 PNEUMATIC THREAD HOLDER FOR LOOMS Leslie J. Hooper, Holden, and Victor F. Sepavich, Worcester, Mass., assignors to Crompton & Knowles Loom Works, Worcester, Mass., a corporation of Massachusetts Application December 13, 1946, Serial No. 715,951

11 Claims.

This invention relates to improvements in pneumatic thread holders for looms and it is the general object of the invention to provide a thread holder so constructed and controlled that a minimum amount of power is required to operate the pump or other source of subatmospheric pressures.

Weft replenishing looms operate with a set of reserve bobbins from which weft ends extend to a thread holder. It is necessary to keep these threads taut and provision must be made to hold the thread of a freshly replenished shuttle when it is picked and also remove this thread when it is cut at the selvage. It has been proposed heretofore to accomplish these general results by means of pneumatic thread holders which however have operated'for a large part of the pick of a loom. Because of this condition it has been necessary to provide an air pump or the like having a large capacity.

It is an important object of our present invention to operate the thread holdin-g pneumatic system of a loom in conjunction with a reservoir in which subatmospheric pressures are built up during the greater part of the pick of the loom by keeping the thread holder mouth closed, and then momentarily open the mouth to suck in any thread which may have been cut at the selvage. In carrying this feature of the invention into effect We open the intake mouth for a short interval of time only, such for instance as a small fraction of a pick starting at or about the time that the lay is on front center, provided a front center selvage cutter is used, but close the intake mouth during the remainder of the pick. We are thus able to develop within the reservoir sufcient subatmospheric pressure to remove the thread by a pump too small to supply such pressure continuously.

It is desirable to provide some form of collector to hold the removed weft ends and it is a further object of the invention to combine the thread collector and pneumatic reservoir in a single unit.

When a freshly replenished shuttle is picked the thread or weft end of the new bobbin must be held to insure threading of the shuttle eye. It is another object of the invention to form the intake mouth in such manner that when it is closed it clamps the aforesaid weft end and holds it independently of pneumatic force. Means operating intime with the loom opens the mouth at the correct time to remove a thread cut at the selvage but closes the mouth just before picking to. clamp the weft end of the incoming bobbin.

With these and other objects in view which will appear as the description proceeds, our invention resides in the combination and arrangement of parts hereinafter described and set forth.

In the accompanying drawings, wherein a convenient embodiment of our invention is set forth,

Fi-g. 1 is a side elevation of a loomA equipped with our invention,

Fig. 2 is an enlarged plan view looking in the direction of arrow 2, Fig. 1,

Fig. 3 is a front elevation looking in the direction of arrow 3, Fig. 2,

Fig. 4 is a vertical section on line 4-4 of Fig. 3,

Fig. 5 is a vertical section on line 5-5 of Fig. 2,

Fig. 6 is a diagrammatic View setting forth the operation of the mechanism for closing and opening the intake mouth,

Figs. 'l and 8 are diagrammatic views showing the operation of the gate or closure for the intake mouth,

Fig. 9 is an enlarged vertical section on line 9-9 of Fig. '7,

Fig. 10 is an enlarged section on line IG-IIJ of Fig. 4,

Fig. 11 shows diagrammatically the variation in subatmosphere pressures within the thread collector with respect to the various positions of the lay, and

Fig. 12 is a diagrammatic View setting forth the invention in its relation to the cloth and a selvage cutter.

Referring particularly to Fig. l, the loom frame I0 supports top and bottom shafts Il and I2, respectively, connected by gears I3 and I4 in the usual manner. A driving gear I5 secured to the top shaft is driven by the pinion I E of a motor M.

The lay 20 is driven by the top shaft by means of connectors ZI, one of which is shown in Fig. 1, in such manner as to pass successively through front, top, back and bottom center positions during a pick or cycle of the loom.

The lay is provided with a shuttle box 22 which receives a shuttle S when the latter is picked toward the replenishing side of the loom. The magazine 25, preferably though not necessarily of the multicolor type, is provided with reserve bobbins not shown from which weft ends W eX- tencl to the thread holder designated generally at H. Weft detector mechanism not shown detects the condition of weft in the shuttle S and when the latter is depleted of Weft calls 0r initiates a replenishing operation during which a transferrer arm 26 moves a bobbin from the magazine into the shuttle. At this time the Weft end W attached to the transferred bobbin moves 3 down with the latter and should be held by the thread holder to effect threading of the shuttle eye not shown during flight of the shuttle which ordinarily starts when the lay reaches substantially top center position.

On the following beat-up of the lay this weft end W attached to the freshly transferred bobbin is incorporated into the cloth or fabric F and extends from the latter to the thread holder H, remaining taut and out of the path of the shuttle until cut at the selvage by a thread cutter 29. The latter may operate in the usual manner either when the lay is at front center, or by connections not shown but Well understood when the lay is at back center.

Except as noted hereinafter the matter thus far described is of common construction and operates in the usual manner. As bobbins descend in the magazine the resulting slackness of their weft ends should be taken up, and when the shuttle is replenished the weft end of the incomingr bobbin should be held by the holder, then Vout at the cloth, and thereafter removed from the shuttle path. These results are accomplished by the thread holder mechanism to be described in detail hereinafter.

In order to develop the subatmospheric pressures already referred to hereinbefore we provide a small air pump driven by a belt 3l from a pulley 32 on the motor shaft 33. This pump 39 isrof small capacity and preferably runs` continuously during loom operation, although certain features of our invention are not limited to continuity of operation of the pump. The latter is connected to a conduit or pipe 95 which leads to a hollow partial vacuum reservoir and thread collector unit designated generally at C. The unit is mounted on an upright 36 supported by the floor on which the looms rests. The unit may comprise a cylindrical member 31 preferably made of transparent material such as plastic and having the right end thereof as Viewed in Figs. 1 and 2 closed by a cap 38 having an exhaust nozzle 39 to which is attached the conduit 35. The cap 38 has a preferably air tight fit with the right end of the cylinder 31 and operation of the .pump 30 creates subatmospheric pressures within the cylinder. The latter is mounted on a support 49 secured to the upper end of the stand 55. e

The left end of the cylinder 31 as viewed in Figs. 1 and 2 is provided with another cap or plate on which are mounted the thread holder H and other parts of the invention which control the time during the pick when the weit ends W are subjected to a pneumatically exerted force.

lPlate or cap 45 has extending from the left thereof as viewed more particularly in Fig. 2 a structure 45 so formed as to provide an interior hollow thread chamber 41. That part of the structure 45 which faces the magazine is provided with an aperture 43 by which the weft ends enter the Chamber 41. The structure 45 is also provided with a second aperture 49, and a vertical thread lslot cut through the floor 5I of structure 45 connects the apertures 48 and 49 and is the means by which the weft ends W' may be lifted from a position below the structure 45 `through the slot to the apertures. The chamber 41 is substantially closed to the atmosphere except for the slot and apertures.

The plate 45 is formed with a wall 55, see Fig. 4, through which extends a member having a lonn gitudinal thread and air passage 51, see Fig. 9. The member 56 is preferably :metallic and se cured in fixed position in the wall 55. andthe left end of passage 51 communicates with the chamber 41. The plate 45 carries a guide 58 which locates the weft ends extending from aperture 48 to aperture 49 close to the intake passage 51'.

The right part of member 56 projects to the right of wall 55 as shown in Fig. 4 and has fitted snugly thereon a deformable tube E5. Tube is preferably made of a soft readily compressible rubber and has its lower side resting on a support 55 fixed to the plate 45. The tube G5 has an interior air and thread passage 61 communicating with passage 51, and these two passages may be considered as an inlet or intake mouth for the unit C. Plate 45 Yis secured to support 49 as at 55, and tie rods 69 hold caps or plates 38 and 45 tightly against the ends of cylinder 31.

It is an important part of our present invention to close the intake mouth throughout the greater part of the pick of the loom and open it only at such times as may be required for removal of a cut thread. This result We accomplish by means of a gate or the like serving as closure kmeans for the rubber tube V65. Secured to the plate 45 are two vertical guides 1l) between which extends a gate or plate 1| having a lower edge 'I2 which may be rounded or otherwise formed .to reduce abrasion of the tube 55. The guide 10 is so located that when the plate 1I is moveddown its bottom edge 12 will cooperate with support B6 and compress the tube and change it from the normal open form shown in Fig. 7 to the thread clam-ping `and mouth closing positionshown in Fig. 8.

The means for raising and lowering plate 1l includes a small shaft 15 rotatable on the plate l5 and extending thro-ugh the latter and having secured thereto an arm 15 located within the cylinder 31 and connected by a pin 11 to plate 1 I. The end'of shaft 15 outside cylinder 31 has secured thereto an arm having a pin and slot connection 3l with a rod 82 slidable in bearings 83 on the plate 45. A collar 84 is secured to rod B2 between the bearings 83 and a compression spring located between the Ycollar and the right hand bearing 83 as viewed in Fig. 6 tends normally to move rod `82 tothe left and thereby depress the plate 1l to move it to the closed position shown in Fig. 8, and in dotted lines in Fig. 6.

ln order to effect longitudinal motion of rod 82 against the action oflpring 85 the lef-t end of the rod as viewed in Fig. 6 is provided with a roll S1 for engagement with the cam 38 having a tappet or point 89. The greater part of the periphery of the cam 88 is circular and the tappet 89 extends over a small part only of the perimeter of the cam.

In order that the cam 89 may be rotated in time with the loom we secure a bevel gear to the top shaft i l and mesh it with a second bevel gear 9E mounted for rotation in a bearing 91 secured to some xed part of the loom, such for instance as the stand 98 on which the motor M is mounted. Extending from bevel gear 96 to the left as viewed in Fig. l is a ilexible shaft |00. The core IDI is secured to and turns with bevel gear 96 as the loom operates. The forward end of shaft Ill is held by a bearing 102, see Fig. 2, xed with respect to plate 45, and the front end of the core is secured to cam 88. During loom operation cam 88 will make a rotation each pick of the loom and the tappet 89 will Ypush the roll 81 from the dotted to the full line position in Fig. 6 once for each pick of the loom.

ln operation, the pump runs continuously to exhaust air from the cylinder 31 and build up in r it e, partial vacuum or subatmospherc pressure.

The instantaneous pressure developed by the pump is relatively small and would be insufflcient to draw the thread through the mouth if the later were permanently opened. When the mouth remains closed for a brief time, however, the pressure within the unit C falls below atmospheric pressure to a point sufficient to draw the thread into the cylinder when the intake mouth is open.

As shown diagrammatically in Fig. 11 the curve a represents the subatmospheric pressure within the unit C and line b represents atmospheric pressure at the outside of the mouth. It Will be seen that pressure within cylinder 31 falls steadily as indicated by the downwardly inclined part of curve a throughout the greater part of the pick corrresponding to the time when plate 1I is down in the position of Fig. 8. When the intake mouth is momentarily opened and in the position of Fig. 1 there will be an inrush of air through the mouth sufcient to draw a thread in the cylinder 31. There will also be a corresponding rise in the pressure within the unit C which however will not reach atmospheric pressure represented by line b due to the fact that the pump continues to exhaust air from cylinder 31.`

When replenishment of the shuttle occurs the lay is on its front center position indicated at fc,

Fig. 1l. As the lay moves rearwardly and reaches approximately its top center position, tc in Fig. 11, the shuttle will be picked. At this time the thread of the freshly inserted bobbin should be clamped by deformation of tube 65, Fig. 8, and this result is attained by having the circular part of cam 88 against roll 81, thereby permitting spring 85 to lower the plate 1|. The shuttle continues in its flight as the lay reaches its rearmost position designated at blcc, Fig. 11, and during the first part of the forward motion of the lay. When the latter reaches approximately its bottom center position, btc Fig. 11, the shuttle will ordinarily be boxed. During flight of the shuttle between top and bottom centers the thread of the freshly transferred bobbin is under tension caused by movement of the shuttle, but will not be able to pull out of the mouth due to clamping.

When the lay again reaches its front center position the thread of the freshly transferred bobbin will be beaten into the fabric F and will extend from the latter to the thread holder. At some subsequent time the temple cutter will cut this thread at the selvage of the fabric, and it should be promptly removed from the loom to prevent it from being whipped into the shed by the shuttle.

If cutter 29 is of the type which operates on front center it will be desirable to open the intake mouth either during or at least immediately after the cutting operation so that the thread released from the cloth can be drawn into the cylinder 31. The pressure changes within the unit C indicated in Fig. 11 correspond to front center operation of cutter 29, the gate being open at fc and remaining open a short time, but being closed before the shuttle is picked.

If, on the other hand, cutter 29 operates at back center while the shuttle is still in flight it will be necessary to keep the intake mouth closed after cutting until the shuttle is boxed. The gate can then be opened and reclosed any time between bottom and top centers, while the shuttle is at rest with respect to the lay.

The interval during which the mouth is actually open and the threads are unclamped is only a small part of the whole time of the pick, and may correspond to no more than 30 of motion of the top shaft. Because of the shortness of the interval it can occur just before front center if a back center cutter is used, or just after front center if a front center cutter is used. In this Way it is possible to keep the mouth closed if desired at front center so that a bobbin moving downwardly'during transfer will not be able to pull its weft end out of the mouth.

From the foregoing it will be seen that we have provided a pneumatic thread control system for a loom wherein the unit C serves the dual function of thread collector and partial vacuum reservoir. The unit has an intake mouth nor mally closed but opened periodically to draw into the cylinder any loose thread which may be in the mouth. The gate 1I and parts operating it constitute control means for the intake mouth closing the latter during flight of the shuttle and holding it closed long enough to enable the pump to build up a sufficiently high partial vacuum to draw` a thread into the unit C when the gate is open. The rubber tube 65 when compressed acts as a clamp to hold the threads against accidental removal from the intake mouth. We do not wish to be limited to the particular means set forth herein by which the mouth can be closed, since it is suiiicient for certain purposes of our invention if the mouth when closed serves as a thread clamp. It will also be seen that We can use a pump of low capacity the instantaneous pressure of which is insuiiicient to attract the thread but which when working in conjunction with the closed mouth builds up a pressure suiciently high to draw a thread into the cylinder 31. When the mouth is made with a collapsible rubber tube as set forth air entering the mouth will tend to expand the tube and open it whenever the gate 1I is lifted from its normal down position. Furthermore, the mouth is open for a short interval of time which may occur immediately after front center if a front center selvage cutter is used, or immediately before front center if a back center cutter is used. In either event the interval of opening can be so placed in the loom cycle by adjustment of cam 83 that the mouth can be closed at front center to prevent a bobbin when moving during a replenishing operation from pulling its weft end out of the mouth. The structure 6 is shown herein for illustrative purposes only and we make no claim for it. l

Having thus described our invention it Will be seen that changes and modifications may be made therein by those skilled in the art Without departing from the spirit and scope of the invention and we do not wish to be limited to the details herein disclosed, but what we claim is:

1. In pneumatic thread holder and remover means for a weft replenishing loom having a thread extending from the cloth, hollow means having an air and thread intake mouth into which the thread extends, control means for the mouth normally keeping the latter closed, means effective to build up subatmospheric pressures within saidy hollow means while said mouth is closed, and means operative to cut said thread from the cloth, said control means causing the mouth to be open subsequent to cutting of the thread to enable the subatmospheric pressures existing within the hollow means to draw the thread pneumatically through the mouth and into said hollow means.

2. In pneumatic thread holder and remover means for a weft replenishing loom having a thread extending from the cloth, hollow means having an air and thread intake mouth into which the thread extends, control means for the mouth normally keeping the latter closed and .clamped against the thread to prevent the latter from moving out of said mouth, means effective to create subatmospheric pressures in said hollow means while said mouth is closed, and means operating to cut the thread from the cloth, said control means causing the mouth to be open to unclamp the thread and enable the subatmospheric pressures existing within the hollow means to draw the thread into the latter.

3. In pneumatic thread holder and remover means for a weft replenishing loom having a shuttle which is picked at a given point in the cycle of the loom and from which extends a thread Which later becomes attached to the cloth, hollow means having an intake mouth into which the thread extends, control means for the mouth keeping the latter closed to clamp said thread for an interval starting prior to said point in the cycle and continuing while the shuttle is in flight, means effective to build up subatmospheric pressures in said hollow means while said mouth is closed, and means effective to cut the thread after the latter becomes attached to the cloth, said control means causing the mouth to `be open subsequent to said interval to unclamp said thread and enable said subatmospheric pressures to draw the cut thread into the hollow means.

4. In a weft replenishing loom in which a lbobbin with a thread extending therefrom is moved during a transferring period from a magazine into a shuttle which is subsequently in flight for a given interval, the thread later becoming attached to the cloth, hollow means having an intake mouth into which the thread extends, control means for the mouth keeping the latter closed during said period and said interval to clamp the thread against movement out of said mouth, means eective to build up subatmospheric pressures in said hollow means While said mouth is closed, and means cutting the thread after the latter has become attached to the cloth, said control means causing the mouth to be open subsequent to cutting of the thread at a time in the loom cycle other than during said period and said interval to enable the subatmospheric pressures within the hollow means to draw the thread thereinto.

5. In a weft replenishing loom having a thread which is rst subjected to tension during flight of a shuttle and is later cut from the cloth, a combined thread holder and remover having an intake mouth into which the thread extends, control means closing said mouth while .the thread is subjected to tension, and means building up subatmospheric pressures within the combined holder and remover while said mouth is closed, said control means being effective to cause said mouth to be open subsequent to cutting of the thread to draw the latter into said combined holder and remover due to said subatmospheric pressures therein.

6. In a weft replenishing loom having a thread which is first subjected to tension during flight of a shuttle and is then cut from the cloth, a hollow thread collector having an intake mouth into Which the thread extends, control means for the mouth closing the latter while the thread is subjected to tension, and pneumatic means pneu.-

matically connected to said collector effective to build up a partial vacuum while the mouth is closed, said control means causing said mouth to -be open to enable the partial vacuum to draw said thread into the collector subsequent to cutting of the thread.

7.' In a pneumatic thread control system for a weft replenishing loom having threads to be removed therefrom, means providing a normally closed intake mouth into which the threads extend, a source of subatmospheric pressures pneumatically connected to the mouth developing low instantaneous pressures insucient to draw the thread into the mouth if the latter were open permanently, a reservoir pneumatically connected to the source and mouth in which during closure of the latter said source develops higher pressures sufficient to draw the thread into the mouth when the latter is open, and means opening said mouth after said higher pressures are developed in said reservoir.

8. In a weft replenishing loom having a thread to be removed therefrom, a combined pneumatic thread collector and partial vacuum4 reservoir unit having a normally closed mouth into which the thread extends, pneumatic means connected to said reservoir creating a given instantaneous subatmospheric pressure too weak to draw the thread into the unit if the mouth were permanently open but eiective due to closure of the mouth to build up subatmospheric pressure within said unit stronger than said given pressure and capable of drawing the thread into the unit when the mouth is open, and means opening said mouth after said stronger pressure has been created within said unit.

9. In a weft replenishing loom having a thread to be removed therefrom, a pneumatic unit serving the dual function of thread collector and reservoir for subatmospheric pressures and having a normally closed mouth into which the thread extends, a source of subatmospheric pressures pneumatically connected to the pneumatic means effective to build up subatmospheric pressures within the pneumatic means which become increasingly larger as the mouth continues to remain closed, and means opening said mouth after a period of closure thereof corresponding to creatio-n within said pneumatic means of a suilciently large pressure to draw the thread thereinto.

10. In a weft replenishing loom having a thread to be removed therefrom, a combined pneumatic thread collector and partial vacuihn reservoir unit, a hollow deformable member communicating with the atmosphere and also with the interior of said unit and through which said thread extends, control means for the member exerting a force thereon effective during part of the cycle of the loom to collapse the member to seal the interior of the unit from the atmosphere and clamp the thread, and means effective to create a partial vacuum in the unit while the member is collapsed, said control means being ineffective during another part of the cycle of the loom to exert said force on the member, whereupon air tends to move through said member into the unit to move the thread into the latter,

11. In a weft replenishing loom having'a thread to be removed therefrom, a combined. pneumatic vthread collector and partial vacuum reservoir unit, a soft elastic rubber tube having a passage therethrough communicating with the atmosphere and alsowith the interior of the unit and normally tending to assume a. form in which said said rubber tube is deformed by said control means, the latter during another part of the cycle of the loom being ineffective to deform said rubber tube.

LESLIE J. HOOPER. VICTOR F. SEPAVICI-I. 

